In the past, various types of sensor sheets which detect a user's finger touch have been examined to improve the interface of an information terminal. For example, a sensor which detects variation of capacitance between the sensor and a human finger by using capacitance detection means is disclosed in Patent Document 1.
In the sensor disclosed in Patent Document 1, a supplemental electrode having lower electrical resistance than a transparent electrode is placed at least partly around the transparent electrode. The sensor disclosed in Patent Document 1 may reduce variation in detection sensitivity.